CAMDEN, N.J. — The sport utility vehicle carrying Gov. Jon S. Corzine was traveling about 91 mph moments before it crashed, the superintendent of state police said Tuesday.

The governor was critically injured when the vehicle crashed into a guardrail on the Garden State Parkway just north of Atlantic City last week. He apparently was not wearing his seat belt as he rode in the front passenger's seat.

The speed limit along that stretch of the parkway is 65 mph.

The state trooper-driven SUV was in the left lane with its emergency lights flashing when a pickup tried to get out of its way. Instead, it set off a chain reaction that resulted in the crash.

Corzine broke his left thigh bone, 11 ribs, collarbone and chest bone. He also fractured a vertebrae in his lower back.

He remained in critical but stable condition Tuesday and doctors were assessing when he might be ready to breathe without a ventilator. Spokesman Anthony Coley said Tuesday the governor was showing improvement.

Doctors have said he doesn't have brain damage or paralysis, and is doing well for someone who sustained so many injuries.

The driver, Trooper Robert Rasinski, could be charged if the state police Motor Vehicular Pursuit Review Board determines the crash was preventable, Superintendent of State Police Col. Rick Fuentes said.

Fuentes said speed was a factor in the accident. A black box inside the SUV recorded the speed of the SUV five seconds before the crash. He said the executive protection unit has the discretion to move through traffic by stepping up its speed and using flashing lights when necessary.

"If it's a non-emergency situation, we would ask them to obey the traffic laws and the speed laws in the interest of safety," he said.

Rasinski and an aide to the governor were not seriously hurt. The trooper will remain out of work until he is cleared by a doctor to return, Fuentes said.

There is no timetable for when Corzine may be able to resume governing the state Senate President Richard J. Codey is acting governor.

Once Corzine is breathing unassisted, he should be able to speak. That milestone would make it possible for physical therapists to do more to help him regain use of his leg — a process expected to take up to six months.

Corzine, a 60-year-old former investment banker, gave up his seat in the U.S. Senate to become governor in 2006.